Production of shockproof expanded plastic sheets



PRODUCTION OF SHOCKPROOF EXPANDED PLASTIC SHEETS Filed March 27,1963 4 Sheets-Sheet l FIG. I

gLa -za FIG. 2

FIG?) INVENTOR. ADOLF KURTZ ATT'YS Filed March 27, 1963 Aug. 30, 1966 A. K RT; 3,270,103

PRODUCTION OF SHOCKPR OOF EXPANDED PLASTIC SHEETS 4 Sheets-$heet 2 FIG. 4

Fl G. 6

1.: WHXTJK INVENTOR: ADOLF KURTZ ATT'YS Aug. 30, 1966 A. KURTZ 3,270,103

PRODUCTION OF SHOCKPROOF EXPANDED PLASTIC SHEETS Filed March 27, 196 3 4 Sheets-Sheet 3 FIG. 7

INVENTOR. ADOLF KURTZ ATT'YS g- 1966 A, KuRTz 3,270,103

PRODUCTION OF SHOCKPROOF EXPANDED PLASTIC SHEETS Filed Marh a1, 1963 4 Sheets-Sheet 4 FIGS FORM AN OPEN NETTING OF THERMOPLASTIC POLYMER Roos APPLYING ADHESIVE TO THE NETTING ADHERING EXPANDABLE POLYMER GRANULATE O THE STICKY NETTTNG PLACING THE NETTING IN A MASTER MOLD BUILDING u ALTERNATE LAYERS OF EXPANDABLE POLYMER GRANULATE AND NET'TINYG FOAMING THE MOLD CONTENTS TO FORM ABLOCK CUTTING THE PLASTIC INTO SHEETS INVEN'IOR: ADO LF K U RT Z ATTWS 3,210,103 PRODUCTION or SHOCKPROOF EXPANDED I'LAS'IIC SHEETS Adolf Kurtz, Fussgonheim, Germany, assignor to lla'dlsehe Anilin- & Soda-Fabrik Aktiengesellsehnft, -LudwlgshIfen(Rhine),-Germany v Filed Mar. 27, 1963, Ser. No.'26 8,3 64

Claims priorily, application Germany, Mar, 31, 1962, j

s Cl'aimsh ta. gems f p The present invention relates to a proc'essfortheprm duction of sheets of expanded plastic'and more particu-. larly to 21 process for the production of shockproof sheetspr'e'ssure and of expanded plastic which are resistant to tensile stress.

It is known to reinforce sheets of expanded plastic by means of layerslof plywood, plastic sheets or expanded metal or also with cement plaster on the outer faces, and thereby to make them resistant to bending and compression' as so-called sandwich panels.

it is a disadvantage of these prior art constructions that as compared with sheets which have not been reinforced they are heavier, have poorer insulating properties in relation to the total thickness, require subsequent'working in the case of sheets cut from a block or produced individually, andin the case of expanded metal reinforcement have a lower resistance to weathering and a greater susceptibility to corrosion.

7 n the other hand it is also known to reinforce COD-2' crete withstecl mesh to makeit resistant to tensile and shear forces. I

The. objectof the present invention istoprovide a process for the production ofshockproof expandedplastic l sheets which are resistant to compression, tension and shrinkage, or walls or partitions consisting of individual expanded plastic-sheets or sheeting which do not exhibit the disadvantages attaching to the prior artsheets. The

sheets prepared according to this invention may if desired be used formaking walls, partitions or ceilings provided with panels and, for insulating layers for walls, floors and ceilings.

I have found, that shockproof expanded plastic sheets or sheetingresistant to compression, tension and shrinkmaster mold partly filled with plastic granulate and adding a layer of plastic granulate, heating the filled master mold as a whole and thereby expanding its contents to form an expanded plastic sheet and removing the finished expanded sheet from themastcr mold after the latter has cooled.

Toprepare simultaneously a plurality of sheets of equal size,'-'a -number 0f reinforcing nctting's or reinforcing frames having a size corresponding to the size of the sheet required 'and'madc 'ofiplastic fibers, plastic wire or other plastic shaped articles are prepared, provided with an adhesive, for example glue, the r'i'ettings or frames thus made sticky eachcombincd and filled with plastic granulnte in a preform, the ncttings or frames surrounded with l plastic granulate introduced consecutively into a master mold provided at the bottom with a layer of granulate, and intermediate layers of 'granulate interposed between the individual netlings or framesythe' master mold then heated as a whole and itscontents expanded into a block containing a plurality of potential'sh'eets each 3,270,103 ,Patei'ited August. 30., .1 .966

. containinga netting or frame,-thebloc k allowed" to cool, removed fronrthe mastermold and parted between the. individual nettingsor frames into a plurality of sheets which may then be assembled to form, walls, .covet'ings opinsulatinglayers;3, 4, 3 1 The essential feature of ,;the inyentive; -concept accordinglyconsists in reinforcing the plastiesheets with plastic;

fibers orsimilar plastic shaped-articles;a closeunion ofthe embedded reinforcement, with the. surroundingexpanded plastic beingachieyed. Qwing to thethigh strength. of themeinforcingmeans andits',low-lweight,,the weight of, thesheet is not appreeiably increasedhut averyef: fective increase in strength isachieved g. 1

For the, continuous. production ,of elongated, sheeting of shocltproof expanded plastic,, ,endless reinforcing webs l inthe form of nettipgandofthe same width asthe sheets are preparel from plastic.fibers,. plastic ,wire or other plastic shaped articles, provided with adhesiyeqand united, with, plastictgranulate, the -reinforcing web; introduced continuously together with the remainder ofthegplasticv granulate into amold space formed by ;tw,o; moving surfaces open at tw o opposite ends said, reinforcing ,web, surrounded by ranulate heated; in ,the interior of the. mold space anl expanded, to anenjdlessexpanded plastic; sheeting, the finishedlexpanded, plastic sheeting removed from the moldspace ,andwoundup oracut into sheets of, any desired length. 4,. r t

,The reinforcing. frame,, may ndyantageously be prepared by making allat crosssgrating of plastic wire, sticking it with glue at the p'oints of,intersection, bending it.

- over a form. to angular, corrugations having flatteped to p'repare'lon'g reinforced webs of expanded 'pl outer surfaces. and; unitingthe; resultantinncr nicrnber of. they reinforcing franteJwithPllat cross-gratings on cac h of the two outer surfacesf, I I

A further increase in 'strength'can beachieved by fillipg the master mold'toward the'outerlsurfaces with slightly preexpanded ,grapitlzit and the.,intermedia'tglayers in the, interior of'the mold. with, strongly P rcexpandedigranulate. In this way hard, abrasion-resistant surfaces;- are .formed.

A further increase in strength while-preserving the low weight maybe achieved by emb'edclin'gfin e. sheets a; reinforcing netting or frame .joif uneven mesh, thev mesh. becoming narr'owerat the edges of the individual sheets; and becoming widei toward [the middle of the sheets.

The finishel sheet's m joined,'togetlier at their, abutting edges, in manner resistant to tensiop, to form walls and ceilings yfme'ansof pointed connection members pressed simultaneously into] two sl 1 eets':, on one side.

or on both sides; I It: is possible by theprocess according t'othts invention I v asticwhich can readily bero'lled'up an,d"bent. For, tihi purpose the reinforcing netting or frame ofpl'asticfib'ers ybe rolled p p r with e r awa n. re Fel a by ia. cal mold, providedlwith adhesive, embedded ir'tigranulate,. the filled block mold he ediand' expanded to formsa block and thelblock then' allowefd'to cool, removed from. the'm'old' and cut spirally to al coher entweb containing, a single layer of the reinforcing netting Qr frame.

The invention wilh'now efurt her,describedwith refcr once to the accompan 'hg rawings in which FIGURES l antic flat cross-grating, FIGURE 3fis an cross-Stating}, 1 I

FIGURE 4 is a" section of a forinfor bending into.- shape the angular corrugated eross gruting oi" FIGURE 3,

FIGURES is an end elevation, of one embodiment of a complete" reinforcing frame comprising an inner memher and two" flat e ress-gratings secured to the outside a 'dfelevation and,v plan. of

cndielevat on' of 1 thereof,

FIGURE 6 is an elevation perpendicular to FIGURE 5, FIGURE 7 is a sectional elevation of a finished reinforced expanded plastic sheet having abrasion resistant surfaces,

FIGURE 8 is a perspec tive'viewof a reinforced plastic web which has been prepared in spiral form ancient, and

FIG. 9 is a block diagram of the process. Flat cross-gratings necessary forreinforcernent of sheets are prepared from plastic wire (FIGURES 1 and 2). For

example drawn and prestressed polyamide wires having a thickness of 0.5 mm. may be used. Preparation of the cross-grating is facilitated if thewires lare stretched parallel to each other over a frame-having notches cut in the edges. The spacing of the notches is equivalentto' the width of mesh of the grating. Wires 2' arestretehed at right angles to the wires 1 onthe top of the wires 1 and in the-same mesh width. Wires 1 and 2 are not interwoven with each other. A suitableadhesive liquid, for example glue, issprayed by means of a spraygun onto the flat cross-grating consisting of the wires loosely laid on one another.

sections 3 (FIGURE 2). 1

To make the inner member of the reinforcing frame as shown in FlGURE 3, a flat cross-grating prepared as described ,above is laid on a form 6 (FIGURE 4) having grooves Sof trapeziform cross section which correspond with the angular corrugations 4 of the inner member. Bymeans of an appropriately shaped counter form (not shown in FIGURE 4), for example a cylinder having,

corresponding grooves, the flat cross-grating is bent into the inner member 7 of the reinforcing frame (FIGURE Cross-gratings similar to that shown in FIGURES I andZ are then laidon the outer surfaces'of the inner 1 member, as shown at 8 and 9, and sprayed with glue.

Union of the intersections 10 of the inner member with the flat cross-gratings again takes place by the glue and a still wire frameis formed. FIGURE 6 is a view of the frame at right angles to that in FIGURES.

This frame is united in a preform with plastic granulate and then laid in amaster mold provided at the bottom with preexpanded plastic granulate. Then intermediate layers of granulate are introduced to fill the interstices in the frame. j A'further layer of granulate is placed on the frame thus filled and a frame laid on this in the same way. Any desired number of frames and intermediate layers of granulate are introduced into the master mold and the whole expanded by heat. The frames are thus closely enveloped on all sides by expanded plastic and the individual particles of plastic weld together.

The block reinforced withframes thus obtained may be cut in the usual way by means of an electrically heated wire or a band saw into sheets. These'sheets, in spite of the reinforcement, have the high insulating value of the non-reinforced sheets of expanded plastic. 0n the other hand they are not heavier than these and have a much higher resistance to shearing, tension andbending than the plastic sheets which are not reinforced. The strength propcrtics of the sheets according to this invention maybe varied within a widerange, according to the requirements placed upon them, by thc choicc of .wire diameter,

mesh width of the grating and also by regulatingthe hardness of the expanded plastic.

'lhe outer portions of the sheets," whieh for static reasons are known to take thebulkjof the stress when the sheets are subjected to bending strain, maybe ,made particularly abrasion resistant and hard. For this purpose the master mold is filled toward the outer surface of the sheets to be prepared with only slightly prcexpanded tinegrained granulate. The internal space of theframe is however filled with coarse-grained strongly preexpanded. plastic granulatc.. After expansion, compacted and harder surfaces 11 are formed (F IGURE 7). These pressure resistant outer layers give in conjunction with the tension resistant grating a very strong sheet resistant to bending.

The wires are thusunited together at the intersmonoa,

If it is desired to prepare a plurality of such shcetsat the same'time in onemaster mold;'the intermediate layers between each two frames are also composed of strongly expanded granulate. After expansion, the block is parted into single sheets in the way described above. Parting is effected; for example by, cuttingl'the bloclcin each case in the middle of a hard layer;-

To .make elongated reinforced sheeting; appropriately long frames opcross-gratings are'rolledup'spirally and in scrted into a cylindrical mold. After filling 'the mold-with plastic granulate; '"theshape is'fullyfexpanc i ed The cyl. indrical blockis allowed to ,ar'td cut spirally to form a coherent web containing a single layer of the reinforcing frame or netting (FIGURE 8').

When expanding simple parts, for-example flower boxe or vases, the strength can be considerably increased by merely embedding a flat grating (as shown in-FIGURES l and-2). =lf the expanded plastic is made soft, the finished sheeting or sheet, provided the dimensions are suitable,

may be wrapped around a tubeor'cdgcd profile without brea hing. I

Plastic sheets which have been reinforced in accordance;

with this invention may be "used widely in; the building" trade for completing exterior'and interior surfaces. '"It is possible in this way to make panels for'walls without additional labor. ing lath latticemay be considerably more widely spaced or may bereplaccd by reinforced framing; In theliningof rafters'in lofts, a span of 65 cm. from rafter to rafter possible to use thesheets as decorative sheets and for packaging goods.- further advantage in the building trade is obtained by'reason of the reinforcement withplas- In the case of ceiling boards, the support kept sutlitic wire. 7 Long insulating webs may be transported as a roll-and installed more simply and cheaply than prior art sheets. This form of construction also offers for insulating circular containers.

Thefollowing tests ilustrate the behavior ofsheet's precompared 1 pared according to this invention under load as with sheets without reinforcement.

Load tests advantages Bending tests carried out on rectangular sheets having thedimensions 20 x 20 x 3 cm. and having been provided with a reinforcement of plastic wire 0.5 mm. in thickness, I without any reinforcement and on sheets of the same size gave the following results:

The reinforced sheet was supported at a width elf p15 em. and a maximum load of kg. (i.e. 7.8 kg./sq. cm.)

was achieved with a deflection of 2.4,cm- Small cracks appeared on the underside of the sheet, but these extended only to the reinforeinggratingc The sheet did-norbrealt.

The sheep without reinforcement fractured under maximum load of 47 kg. (i.c a surface-load of 5.8 ltg.'/sq.

cm.),the deflectionbcing 1.2 cm.

By making the reinforced plastic sheet harder, -it is capable of withstanding even higher loads. This was clearly shown .by a piercing test in which the sheet; was.

laid on a circular support having a diameter of 8.5 cm. and

pierced by a spike having a diameter of 2 cm. .A force of I 109 ltg. wa s required to-picreethe reinforced sheet, whereasthe sheet without reinforcement was piercedwith a load of only Zl kg.

. t 1 claim: l. A process for the production of shocltproof plastic expanded sheets useful as sheeting for walls, ceilings, pan-- master mold to cool and removing the expanded sheet therefrom.

2. A process for the production of shockproof expanded plastic sheets as claimed in claim 1 which comprises making simultaneously a plurality of sheets of the same size by preparing a plurality of said reinforcing netting, providing each of the said reinforcing nets with adhesive, uniting each sticky reinforcing net thus obtained in a preform with expandable plastic granulate, providing a layer of expandable granulate at the bottom of a master mold,

consecutively introducing the nets with united granulate into said master mold with intermediate layers of expandable granulate therebetween,- heating the entire master mold so that its contents expand to form a block containing a plurality of sheets, allowing the master mold to cool and removing said block which is then severed parallel with said netting into sheets.

3. A process for the production of shockproof plastic sheeting which comprises preparing a continuous reinforcement web of an open netting of thermoplastic polymer rods, providing the net web with adhesive, uniting the sticky net web with an expandable plastic granulate, passing the net web together with the additional expandable plastic granulate continuously into a mold space formed by two moving surfaces open at two opposite ends, heating the reinforcing net surrounded by expandable granulate in the interior of the mold space to expand it to an endless expanded plastic sheeting, and removing coming narrower at the edges of the individual sheets and becoming wider toward the middle of the sheets.

6. A process which comprises rollingup a reinforcing netting of thermoplastic polymer rods to produce a spiral with regular gaps, providing the spiral with adhesive, uniting the sticky spiral with expandable plastic granulate, introducing the granulate-covered spiral into a cylindrical block mold, filling the void space in the mold with expandable plastic granulate, heating the filled block mold to cause expansion to form a block, allowing the mold to cool, removing said block and cutting said block spirally into a coherent web containing a single continuous layer of reinforcing netting.

References Cited by the Examiner UNITED STATES PATENTS.

2,954,589 10/ 1960 Brown 264-46 2,962,407 II/ 1960 Aykanian 26447 3,037,897 6/1962 'Pclley 264-47 XR 3,043,627 7/ 1962 Torjusen 264-46 XR 3,081,488 3/1963 Casavina et al. 264-'-45 XR 3,091,998 6/1963 Wehr et al. 246 3,124,626 3/1964 Graham et al 264-45 3,157,144 ll/1964 De Jarnett 264-45 XR FOREIGN PATENTS 841,647 7/1960 Great Britain.

ALEXANDER H. BRODM ERKEL, Primary Examiner. P. E. ANDERSON, Assistant Examiners. 

1. A PROCESS FOR THE PRODUCTION OF SHOCKPROOF PLASTIC EXPANDED SHEETS USEFUL AS SHEETING FOR WALLS, CEILINGS, PANELLED WALLS OF INSULATING LAYERS FOR WALLS, FLOORS AND CEILINGS WHICH ARE RESISTANT TO PRESSURE, TENSION AND SHRINKAGE WHICH COMPRISES PREPARING A REINFORCING, OPEN NETTING OF THERMOPLASTIC POLYMER RODS DIMENSIONED TO CORRESPOND TO THE SIZE OF THE SHEET, PROVIDING SAID NETTING WITH ADHESIVE, UNITING THE RESULTANT STICKY NETTING WITH EXPANDABLE PLASTIC GRANULATE, PLACING THE RESULTANT PRODUCT IN A MASTER MOLD PARTLY FILLED WITH EXPANDABLE PLASTIC GRANULATE, ADDING A FURTHER LAYER OF EXPANDABLE PLASTIC GRANULATE, HEATING SAID FILLED MASTER MOLD AND THUS EXPANDING ITS CONTENTS INTO AN EXPANDED PLASTIC SHEET, ALLOWING SAID MASTER MOLD TO COOL AND REMOVING THE EXPANDED SHEET THEREFROM. 